According to Rachel Barker, in conversation with Tate curator Mark Godfrey, Mr. Richter:
“Frequently paints quite detailed under-paintings which he might muse over and consider for some time. This is an extraordinary process bearing in mind that 90% of this image will be permanently hidden by subsequent paint coverage.
“So, after the under-painting is determined ready Richter then covers it with thick oil paint, sometimes using wide headed brushes but more frequently with his squeegee. The squeegee usually comprises a length of flexible Perspex fitted with a wooden handle. The edge of the Perspex is used to etch, scrap or smear the paint across the surface of the work. In the film showing Richter painting we also see the artist distributing oil paint along the length of the squeegee and then applying it to the surface. This creates a smooth buttery wet into wet surface on which to start ‘disturbing’ the paint.”
Read the rest here.